


set your old heart free

by spiralpegasus



Series: Sylvix Week 2019 [2]
Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe - Soulmates, Angst with a Happy Ending, Implied/Referenced Child Abuse, Kidnapping, M/M
Language: English
Status: Completed
Published: 2019-10-14
Updated: 2019-10-14
Packaged: 2020-12-16 06:20:59
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,148
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21031649
Author URL: https://archiveofourown.org/users/spiralpegasus/pseuds/spiralpegasus
Summary: Felix and Sylvain have been bonded since they were small. Fear of potential repercussions has kept them quiet their whole lives, but when something happens to Sylvain, keeping it a secret isn't an option anymore.Or, soulmates share thoughts, and when Sylvain is taken, Felix is his only hope of rescue.Sylvix Week 2019 Day Two: Soulmates





	set your old heart free

**Author's Note:**

> title is from hello my old heart by the oh hellos because they're all i listen to when i write sylvix apparently
> 
> there are some references to miklan's abuse of sylvain, as well as vague references to sylvain engaging in some very questionable intimate activities as a young teenager with much older women. nothing is very graphic

Felix is nine when Sylvain kisses him for the first time.

Sylvain had been joking when he gave all his friends a peck on the lips; soulmates form a bond at first kiss, and everyone their age thinks it’s gross and silly. “Just to see if we’re meant for each other!” he’d said with a grin, leaning in with exaggerated _mwah_s to kiss Ingrid and Dimitri. He’d clearly expected the same when he kissed Felix – just a tiny, chaste little thing, a playful imitation of what grown-ups do. 

Felix is nine, and Sylvain is twelve, and they tumble into each other’s minds and hearts with all the grace of newborn horses.

_Felix? Sylvain? Is that—Are you—Get out of my—it’s okay—You’re warm—You think fast—slow down, I can’t—quiet—quiet—_

“Did it work?” Dimitri interrupts them, hushed. Felix wades out of the mess that’s become his thoughts and returns, more or less, to reality. Dimitri and Ingrid are staring at the two of them, wide-eyed.

_I guess so—my dad’s gonna be so— _happy-_mad—this is—_cool-_scary—_

“Holy shit,” Sylvain croaks.

“Don’t say bad words,” Ingrid says automatically, but her amazed expression doesn’t change. “You two—you’re soulmates?”

_Yes._ No. _You can’t be—why don’t you want—_

“Y-yes,” Felix stammers, his mind abuzz with both his thoughts and Sylvain’s, whirling together and crashing around each other like rivers around rocks. 

“I…” Sylvain looks pale for some reason. His thoughts are swirling around Felix’s, so fast as to be barely comprehensible. Felix tries to grasp at them, tries to figure out what Sylvain is thinking, but he’s like a stormy ocean in the middle of the night. Rough, dangerous, dark. Felix can only grab a few words from Sylvain’s thoughts, and none of them make much sense.

_Bad—danger—scared—want—lonely—need—_

“Sylvain,” Felix whimpers, latching onto Sylvain’s sleeve, because he might not understand what’s going on in Sylvain’s mind but it’s bad. Is it that horrible, learning Felix is his soulmate? Does he hate Felix—

_No!_

The strength of Sylvain’s refusal has Felix physically recoiling. Don’t understand, can’t understand—scared, Sylvain’s thoughts plead, before receding back into the dark, frightening ocean of his mind.

“What’s wrong?” Felix begs, pulling on the fabric of Sylvain’s shirt.

“I need to go,” Sylvain says with a smile. It’s fake, and Felix knows, and Felix would have known even without the bridge between his mind and Sylvain’s. “My father wants me back early tonight.”

_Don’t lie,_ Felix pleads, hoping Sylvain is listening.

If Sylvain hears him, he does not acknowledge it. Dimitri and Ingrid cry out after him, but Felix can’t move, shaken to his core at the sheer depth of pain he’d glimpsed in Sylvain’s heart.

Felix is nine when he learns that the Gautiers hate soulmates.

“I never would have kissed you if I thought this would happen,” Sylvain says desperately. “When my family learns I found my soulmate—Goddess, when they learn my soulmate is a _boy—”_

“Then don’t tell them,” Felix says. He’s clinging to Sylvain’s hands, as if he can soothe the wild, violent river of Sylvain’s painful thoughts with a physical touch. “Why—why do they even care so much?”

“You can’t have a soulmate if you’re gonna defend the border,” Sylvain mumbles, sounding like he doesn’t quite understand it himself. “We—we have to marry the right person. Have an heir. Pass on the Lance of Ruin.” His thumbs drag across the backs of Felix’s hands. His nails have scars around them, and when Felix touches them, he gets a spike of _dark-cold-wet-Miklan-help-sorry_ before Sylvain slams a lid on the memory. “Having someone in your head—it’s a liability, in a lot of ways, you know?”

Felix thinks he gets it, kind of – being bound to the wrong person could create a leak of very sensitive information that would be almost impossible to stop. Even if it’s the right person, a weapon of the Kingdom must prioritize the Kingdom’s safety above all else. Not the person in the back of their mind, begging them to come home safely. But still—but still—

“That’s stupid,” he snaps, because those are a lot of big thoughts and big feelings, and he’s never been good at putting words to those.

Sylvain cracks a grin. “Yeah,” he whispers, eyes shining with a painfully tender fondness, and Felix is struck then by the depth of what they share. All the thoughts he’d been unable to communicate with his words – they were there, laid bare for Sylvain to see.

He feels understood. He feels vulnerable.

But it’s Sylvain, who’s held him countless times as he cried over the dumbest things. Felix has never been anything but vulnerable with him.

“We can’t tell them,” Sylvain says, and his mind whispers _I have to keep you safe._ Felix thinks of the echoed memory of the bottom of a well. “They’ll—I don’t know what they’ll do. But we can’t tell them.”

“We’ll have to tell Ingrid and Dimitri not to say anything, too,” Felix says. _Worry-fear-trust._ He tightens his grip on Sylvain’s hands. “They already know.”

A hollow laugh. _I’m broken and they’ll know,_ is what that laugh is saying, and Felix smacks Sylvain’s shoulder.

“They love us,” he snaps. “They’ll keep it secret.”

_Love,_ Sylvain’s mind titters, almost like it’s a scandalous joke that Felix is telling. Felix tries to shove back at it—_love! I love you! They love you!_ It’s a petulant exchange of thoughts that has Sylvain laughing out loud. It’s a genuine one, though, not the empty one Felix hates. 

Ingrid and Dimitri agree to keep it quiet, though they’re clearly unsure about it. The back of Felix’s mind where Sylvain lives becomes quieter, easier to manage. It’s less a constant crash of sensation and more a constant warm buzz of white noise; he can pick out words and images if he focuses, but for the most part, it’s a very generalized idea of what Sylvain is thinking and doing unless Sylvain deliberately pokes at him to get his attention. 

Surprisingly, it doesn’t change their lives as much as Felix thought it would. Mostly he just has to work very hard not to react to the ridiculous thoughts Sylvain subjects him to. What’s difficult is—

_—Miklan, stop, hurts, sorry—_

—well, what’s difficult is experiencing for himself the kind of pain Sylvain’s smile hides.

As the years pass, he can only bear witness to the increasingly twisted nature of Sylvain’s thoughts. Margrave Gautier puts more and more pressure on Sylvain to find a suitable match, because of course skirt-chaser Sylvain hasn’t gotten involved in any of that soulmate nonsense, as it should be for a Gautier.

His pursuit of women becomes less of a playful way to distract from his ever-growing closeness to Felix and more of a way to damage himself and the people around him. Even when Felix is far away, he catches flickers of the women Sylvain chases, ugly and dead-eyed through the filter of Sylvain’s thoughts. He lifts a noblewoman’s hand up to his lips and kisses her knuckles.

_I’ll do it on my terms,_ Sylvain’s mind rings viciously, clear as a bell, as he stares the woman right in the eye. _I’ll break my heart on my terms, and if I’m lucky, I’ll break yours too._

_Sylvain,_ Felix pleads from miles away, grip tightening on his sword. He’s only eleven, and Sylvain only fourteen, but the both of them are familiar with emotions much more mature than they are. 

The woman is much older than Sylvain is. This much Felix can tell, even through the fisheye lens of Sylvain’s perception. She doesn’t care, and doesn’t care if Sylvain cares. Noble, Crest-bearer, Gautier. That’s all she sees. She doesn’t see the scared boy whose thoughts curl up next to Felix’s like frightened animals, doesn’t see the bruises and the suffering behind Sylvain’s practiced smile.

She does see the rest of Sylvain, though, and Felix sobs as he tries to train hard enough to distract from the hopelessness of Sylvain’s submission to her whims. When it’s over, and all Sylvain can say is _I’m sorry you had to feel that,_ Felix screams and breaks his wooden sword in half on the training dummy. Because if Sylvain can care about Felix hurting, why can’t he care about himself?

Training becomes his only escape from the things Sylvain subjects himself to, not only because he can’t bear to experience it while entirely in his own mind, but because Sylvain’s admitted to him that Felix’s mind becomes a comfortable bastion of emptiness when he gets into the rhythm of his routine.

A year passes.

Glenn dies.

Sylvain can’t come to Felix’s side until the Gautiers receive official news of the tragedy. He spends three long, agonizing days trying to get through to Felix, who barely eats and only sleeps when his body gives out on him during training. When he realizes Felix isn’t listening, he starts pushing as much _love-support-grief_ along the link as he can; it’s a solid wall of warmth for Felix to fall back against in his mind. When Sylvain finally arrives physically, Felix can’t bring himself to care about who can see them when he pulls Sylvain into a tight hug and refuses to let go.

“They’re just friends supporting each other in a difficult time,” he overhears Rodrigue soothing the Margrave. He buries his face into Sylvain’s chest and doesn’t move; he has to be carried to his room.

He doesn’t see Sylvain for years after that. The link is a constant source of comfort, although Felix denies it when pressed. Ingrid is a bereaved shell of her former self. Dimitri has been replaced by an animal wearing a human face. There’s a rift between Felix and his father that neither can seem to bridge. But Sylvain—smiling, suffering Sylvain, his mind full of tumultuous thoughts, his heart full of warmth for Felix – Sylvain stays the same.

By the time they attend the Officers Academy together, Felix is beyond used to hiding his internal communications with Sylvain; he couldn’t exactly laugh at a crude joke while sitting at a silent dinner table with his father. Sylvain flirts with women and laughs when he’s asked about his soulmate. Few people approach Felix about anything, let alone about soulmates. 

They don’t kiss, or fuck, or do anything romantic soulmates should, but there’s nothing platonic about their bond. Felix wakes hard and sweating from dreams whose origin he can’t determine, him or Sylvain. Sometimes Sylvain crawls into bed with Felix on nights when the dark river of his thoughts is particularly violent. Sometimes Felix does the same. Ingrid and Dimitri eye them from time to time, but the secret stays secret.

Until it doesn’t.

* * *

Felix wakes up to a silent mind.

This is unusual for many reasons. Sylvain’s thoughts are a constant buzz, flitting from topic to topic, calculating and recalculating everything he does. Even if Felix is awake while Sylvain is asleep, Sylvain’s dreams are dark, restless things that prowl in the back of Felix’s head like circling wolves. Sylvain usually wakes up before Felix does besides – in fact, it’s usually some unintentionally loud thought of Sylvain’s that wakes Felix up in the morning in the first place.

He hasn’t overslept by any means. The first breakfast bell hasn’t even rung yet. But there isn’t even the mutter of Sylvain’s dreaming thoughts in his head, which—well, it’s happened before when Felix woke while Sylvain was in a deep sleep, but not often.

It’s unusual, but not necessarily alarming. Still, there’s a tug on his heart somewhere saying _worry, look, make sure._ He raps his knuckles on Sylvain’s door down the hall, and when there’s nothing but silence, he grabs the doorknob.

Sylvain’s bed is empty.

Not only is it empty, it’s like he never slept in it. Sylvain is meticulous, but even he doesn’t make his bed first thing in the morning – he tidies up later, when he returns from breakfast to grab his materials for class. 

It’s just an empty bed, but Felix’s heart freezes. He grabs onto his link with Sylvain and _tugs._ He hates it when Sylvain does it to him because it scares the shit out of him every time, so if Sylvain is sleeping, it will wake him right up.

His mind stays silent.

Sylvain’s room tilts sideways as Felix’s heart begins to race. Sylvain isn’t just sleeping, he’s unconscious. He’s not in his bed. Where did he go last night? He goes out so often, to so many places. Felix remembers briefs snippets of conversation, of a tavern, of a beautiful girl with dark brown eyes, and then he dozed off to the ebb and flow of Sylvain’s usual flirtatious thoughts.

Someone took Sylvain, and Felix didn’t even wake up. What a stupid, useless soulmate he is.

“Shit,” he whispers, grabbing a handful of his bangs and pulling. “Shit. Fuck.” He gives the bond another jerk, and it’s like trying to move a limb that’s dead asleep. No response. Numb. He can imagine the Professor’s face if he goes to them with this – _Sylvain didn’t sleep in his own bed last night? What else is new?_ How can he explain why he knows something is wrong without giving away the secret he and Sylvain have worked so hard to protect?

“Felix?” the boar’s voice comes from the door. “Is something wrong?”

“Sylvain,” Felix chokes out. He turns to face the boar, whose expression becomes increasingly alarmed at whatever he sees in Felix’s eyes.

“Is he hurt?” Dimitri asks lowly. He may have lost most of what made him one of Felix’s best friends, but his oath to secrecy is not something he’s forgotten. “Can you speak to him?”

“It’s empty,” Felix tries to snap, but his voice breaks. “It’s silent. I—I don’t know—” He wrenches at his hair again, his feet carrying him in a restless loop around Sylvain’s room. “Something’s wrong, and he’s not waking up.”

“Is…” Dimitri draws in an audible breath. “Is he—”

“I think I’d know if he was fucking _dead!”_ Felix shouts, whirling on Dimitri with directionless fury.

Dimitri is infuriatingly calm in the face of Felix’s anger. “We need to speak to the Professor,” he says.

The laugh that tears itself from Felix’s throat is ugly and humorless. “No one can know, remember?” he hisses.

“You’re both much older now, with much more independence.” Dimitri eyes him with something infuriatingly close to pity. “The both of you and your reputations can survive the blow.”

Felix starts to pace again, returning to his link to Sylvain like something will change if he just pulls on it hard enough.

“I’ll go speak to them,” Dimitri says softly. Felix scoffs, but when he makes no attempt to protest, Dimitri leaves.

Felix hates this helplessness. A tavern, a girl, brown eyes. Dark brown, darker than his, darker than Sylvain’s. Plenty of people have dark brown eyes, but that particular shade is more common in northern Faerghus.

A frustrated noise escapes unbidden. Eye color isn’t enough to assume origin. Marianne’s eyes are brown, too, and she’s from the Alliance. There has to be something else in his memories of Sylvain’s thoughts that will give him some kind of clue.

A tavern, a girl, brown eyes. Some kind of alcohol – sweeter than he’s used to, because Felix remembers Sylvain nudging him about that. A voice, lilting around a light accent. He’s heard it somewhere before, but plenty of people who come to the monastery have accents and he can’t place his finger on its origin.

Sweet alcohol. Not fruity, really. He rolls the memory on his tongue. Things got blurry after that, and he thought it was because Sylvain was getting drunk, but—maybe the sweetness was a poison of some kind. A drug.

This process would be so much easier if Sylvain was awake for Felix to question, but he can’t just sit on his ass while Sylvain is in danger, hoping Sylvain will wake up eventually.

He strides down the hall and bangs on Claude’s door.

“Ye-es?” Claude asks as he cracks his door open. He’s mostly dressed, but his overcoat is still draped over the back of his chair.

“How much do you know about drugs that render people unconscious?” Felix asks bluntly.

Claude squints, eyeing him up and down. Felix must make quite a sight. He’s still in his nightclothes, his hair in the braid he slept in, his bangs a mess. Whatever Claude sees, it makes him pull the door open farther, a serious expression on his face.

“Normally I’d ask you why you need information about something like that first thing in the morning,” he says, a shadow of playfulness in his voice, “but I suspect you’d cut me down where I stand.”

“Just—do you know anything or not?” Felix snaps, clenching his fists. “Something you put in a drink that might make it taste unusually sweet.”

“Huh,” Claude says, tilting his head. He sits in his desk chair, drumming his fingers on its back thoughtfully. “Well, it’s not something I’ve personally worked with, but I know of a drug like that.” He gives Felix a sideways look. “I would expect _you_ to be more familiar with it than I am.”

“What the fuck is that supposed to mean?” Felix snarls.

Claude raises his hands placatingly. “No, it’s just—it’s made from plants that only grow in northern Faerghus.”

A tavern, a girl, brown eyes. Northern Faerghus brown. A lilting accent, a plant that only grows up north.

The accent—he’s heard it before, in Gautier territory. Near the border, to be specific.

“Sreng,” Felix whispers.

“I mean, I guess it probably grows in Sreng, too,” Claude says with a shrug. “It just needs someplace cold and dry.”

“I have to go.” Felix practically sprints out of the room. He remembers halfway down the hall that he’s still in his nightclothes and can’t very well tear apart whoever took Sylvain without his sword.

Once he’s dressed, his sword on his hip, he thunders down the dormitory stairs. Dimitri, the Professor, and the rest of his class are at the bottom, milling about uncertainly, all dressed for battle.

“Dimitri has explained the situation to me,” the Professor says. They’re outwardly calm, but there’s a line of tension in their face that Felix knows to look for. “I understand you believe Sylvain has been taken.”

“He was drugged at a tavern last night,” Felix says, crossing his arms to hide his shaking hands. “People from Sreng took him.”

“Did he wake up?” Ingrid asks urgently, grabbing Felix’s bicep in a white-knuckled grip. “Did he tell you?”

Felix jerks away from her grip. “No. I figured it out from what I remember of last night.”

“Were—were you with him or something?” Annette asks, brow furrowed. “Or—” Her eyes widen, and her hand flies to her mouth. “Oh! Oh, you two are—”

“Be quieter,” Felix hisses. When Annette wilts, he softens immediately, averting his eyes. “I—yes, he’s… he’s my soulmate. But you can’t tell anyone, do you understand?”

“Whyever not?” Mercedes asks, a gentle frown on her face. “Soulmates are a gift from the Goddess. You should be proud to share your bond.”

“Tell that to his family!” Felix snarls. “It’s—it’s not important right now, anyway! We have to find him before—”

Something shivers in the back of his mind, and he stops immediately. He gives the bond another tug, gentler than before. _Sylvain?_ he coaxes.

_Scared—dark—cold—_ inside of a carriage, pain in his wrists, aching head _—scared—scared—scared—_ brown eyes, cruel smile _—cold—scared—_

“Felix?” the Professor asks patiently.

“Shut up,” he hisses. “I’m listening.”

_Where?_ he tries to ask. _Where? Hurt? Where? See?_

_Sreng—hurt—north—take—_

Felix flips through vague impressions of a carriage, a brown-eyed girl, men in fur coats. Sylvain is barely conscious, his thoughts creeping through a haze of incoherency, but Felix catches a glimpse of the trees that grow in Fraldarius territory.

“We need to go to Faerghus now,” he says shortly. “Through Fraldarius territory. I think they’re on the main road going north.”

“If we hurry, we may catch them,” the Professor says. “Everyone, ready your mounts. I’ll tell Seteth we have an important training exercise with the Fraldarius knights.”

_Felix, don’t—_

_Of course I’m coming, you fucking idiot,_ Felix snarls, hoping at least the sentiment gets across, if not the words. 

There’s muted protest, but it’s blanketed by so much raw relief that Felix feels his eyes sting. Sylvain thinks himself so useless, so unlovable. The complexity of his suffering leads him to do things that hurt Felix as well as himself, but Felix can’t imagine he’s any easier to be bound to.

_I’m coming. I’m going to save you._

Sylvain slips into the darkness again.

* * *

The Professor pushes them hard; the marching pace is absolutely brutal. No one complains. Felix goes silent at irregular intervals as Sylvain drifts in and out of consciousness, focusing all his energy on doing what he can to soothe the pain Sylvain is in. He suspects the Sreng natives who took him are taking out their anger at Faerghus on him, but Sylvain is too incoherent for him to tell.

_Help,_ Sylvain begs, past the point of telling Felix not to bother saving him. _Hurts. Please. Help._

_I’m coming,_ Felix tries to say, desperate, his heart aching. _Hold on. I’ll kill every bastard who hurt you. Hold on. I’m coming._

_Felix. Felix._

Felix pushes as much _love-support-presence_ as he can along their wavering link. The carriage tracks they’re following along the North Road are getting fresher. They’re pushing their horses hard, and there’s no way a carriage can stay ahead of them for long, even one that departed hours earlier.

“We’re getting closer,” the Professor says, slowing their horse. “We need a plan.”

“Kill them,” Felix says shortly.

“Well, the group that took him is probably small,” Dimitri reasons. “They likely want to get back across the border as quickly as they can. Larger numbers would be unwieldy.”

“So we kill them,” Felix repeats, his grip on his reins tightening.

The Professor sighs. “We won’t have much of an element of surprise approaching them on the road as we are, anyway.”

“I will take the vanguard,” Dedue says. His face is drawn tight with an anger Felix is used to seeing directed at _him,_ not at anyone else. “I will draw their attention.”

“I’ll cover everyone from the back,” Ashe pipes up.

“I’m not so good at mounted combat,” Annette frets. “Can I get off my horse?”

“I imagine we’re almost on top of them by now,” the Professor says, eyeing the hoofprints and wagon tracks in the cracked, frozen dirt. The road is too winding and forested to see very far ahead, but if Felix strains his ears, he can hear the faint sound of voices. “Everyone who’d rather not fight on horseback, dismount now.” Annette, Mercedes, Dedue, and Felix all slide off their horses.

They approach as quietly as they can, but it’s inevitable that they’ll be spotted before they can attack. One of the men at the back of the wagon lets out a shout. An arrow misses Felix’s shoulder by scant inches.

_Felix—_

Sylvain’s voice is in his head, begging him for rescue, for his safety. Felix draws his sword and sprints for the wagon.

The battle is short and bloody. The boar was right; this was a small strike force, not prepared for much combat, especially not against the elite students of the wielder of the Sword of the Creator. Splattered with his enemies’ blood, Felix drops his blade carelessly on the ground and clambers into the wagon.

It’s dizzying, seeing himself through Sylvain’s eyes. Felix. _Rescuer, hero, knight in shining armor._ Some of the impressions are playful, joking, but with an edge of sincerity that has Felix dropping to his knees at Sylvain’s side.

Sylvain is bound at the wrists and ankles, a gag in his mouth. He’s bruised. Bloodied. Barely clinging to consciousness.

Prying the gag from Sylvain’s mouth, Felix gathers Sylvain’s form against his chest. “Alright?” he whispers.

_Warm safe hold me tighter was scared you wouldn’t come—_ “Now that you’re here,” Sylvain jokes hoarsely.

_I’ll always come I’m with you til we die I love you I love you—_ “Cracking jokes at a time like this?” Felix says, holding him tighter. Sylvain is too cold in his arms, shivering in the Faerghus chill. All he has is his uniform jacket. Felix unclasps his fur cloak and drapes it over Sylvain’s body.

_I’m sorry—don’t be sorry—I hurt you—I don’t care—I love you—I love you._

Felix presses their foreheads together and lets Sylvain cry.

**Author's Note:**

> that's a wrap! thanks for reading! also, imagine having someone like sylvain in your head 24/7. or felix, for that matter.
> 
> sylvain: you've had annette's song about crumbs and yums stuck in your head all day  
felix: I CAN'T HELP IT


End file.
